1. Field of the Invention
The present invention relates to a reject device for a high-speed packaging machine for continuously producing aseptic sealed packages, containing pourable food products, from a tube of packaging material.
2. Brief Description of the Related Art
Many pourable food products, such as drinks, fruit juice, pasteurized or UHT (ultra-high-temperature treated) milk, wine, tomato sauce, etc., are sold in packages made of sterilized packaging material.
A typical example of such a package is the parallelepiped packaging container for liquid or pourable food products known by the name of Tetra Brik Aseptic (registered trademark), which is formed by folding and sealing a strip-rolled packaging material.
The rolled packaging material comprises layers of fibrous material, e.g. paper, covered on both sides with thermoplastic material, e.g. polyethylene; and the side of the packaging material eventually contacting the food product in the package also comprises a layer of barrier material, e.g. an aluminium sheet, in turn covered with a layer of thermoplastic material.
As is known, packages of the above type are produced on fully automatic packaging machines, on which a continuous tube is formed from the packaging material supplied in strip form. The strip of packaging material is sterilized on the packaging machine, e.g. by applying a chemical sterilizing agent, such as a hydrogen peroxide solution; following sterilization, the sterilizing agent is removed, e.g. vaporized by heating, from the surfaces of the packaging material; and the strip of packaging material so sterilized is kept in a closed sterile environment, and is folded and sealed longitudinally to form a tube.
The tube is filled with the sterilized or sterile-processed food product, and is sealed at equally spaced cross sections at which it is then cut into pillow-pack packets, which are subsequently folded mechanically into parallelepiped packages.
Known packaging machines normally comprise a reject device for rejecting any packages not guaranteed perfectly aseptic.
Such devices substantially comprise a supply station supplied successively with the packages; first guide means for guiding the packages along a transfer path to an output station; second guide means for guiding the packages along an expulsion path intersecting the transfer path; and a selecting member comprising a movable partition located at the intersection of the two paths, and rotating about a fixed hinge axis between a first operating position connecting the supply station and the first guide means, and a second operating position connecting the supply station and the second guide means.
A major drawback of reject devices of the above type is that, as the output rate of the packaging machine increases, the movable partition tends to interact abnormally with the packages fed through at high speed, and is subject to jamming, thus resulting in stoppage of the production cycle.